Singulating items from a bulk supply is a difficult task, particularly where the items must be precisely counted, such as is the case with pharmaceuticals. The singulating task is complicated by the fact that the device for singulating often times must be able to singulate items of varying sizes, shapes and weights.
One example of a singulating device and counter is found in U.S. Pat. No. 4,018,358 entitled Cassette Pill Storing, Dispensing and Counting Machine. In that patent, different types of pills are stored in separate cassettes which may be operated by a dispensing machine for dispensing from the cassette into a vial. The dispensing machine provides a vacuum supply and a rotary drive for operating a wheel in the cassette having a series of openings annularly arranged to pick up pills in the bottom of the cassette under vacuum pressure and carry them to a discharge opening. A separator wall extending across the line of travel of the holes carrying pills deflects the pills through the discharge opening. A gauge is adjustable to overlie a portion of the openings in the wheel to vary the opening size so that only a single pill is carried by each opening. A photoelectric cell triggered by a fiber optic scanner at the discharge opening counts each pill. An agitator turns with the conveying wheel to break up pills bridged together. A switch is utilized to set an electronic counter to the number of pills desired. This counter then successively counts down until it reaches zero at which point the machine stops.
Another example of a singulating device and counter is found in U.S. Pat. No. 4,697,721 entitled Pill Storage and Dispensing Cassette which discloses an improved pill storage and dispensing cassette having front and back side walls, opposite end walls, and opposite top and bottom walls defining a storage chamber therein. A rotatable pill conveying wheel is positioned in the back side wall and has a plurality of openings for holding and conveying a pill to a discharge chute upon actuation of a remote vacuum source. A separator member is positioned over the openings of the conveying wheel to dislodge the pills from the conveying wheel and such that the pills fall through the chute into the desired receptacle. An adjustment shoe is provided so that only one pill is held and conveyed by each opening in the conveying wheel. A central wall is included within the cassette to divide the pill chamber into forward and rearward compartments with the pills being primarily stored in the forward compartment with a limited number of pills passing through a recessed area in the central wall to the rearward compartment for conveyance by the conveying wheel. An agitator is positioned within the rearward compartment for rotation in the opposite direction as the conveying wheel to agitate the pills and prevent bridging across the top surface thereof. An insert is provided at the opening of the discharge chute to direct the dislodged pills into a receiving vial. The cassette is used in conjunction with a counter that provides a source of rotary motion for the conveying wheel as well as a vacuum source.
Another example of a singulating device and counter is found in U.S. Pat. No. 6,561,377 entitled Vacuum Drum Pill Counter which discloses a vacuum driven pill counter having a counter housing with a pill discharge aperture formed therein. An integrally formed vacuum drum is rotatably positioned in the housing and the vacuum drum includes a front wall, a rear wall, and a perimeter wall. The front wall of the vacuum drum has a plurality of pill apertures formed therein. A vacuum source communicates with the housing such that the vacuum sources is capable of drawing a vacuum through the pill apertures formed in the vacuum drum and a torque source is operatively connected to the vacuum drum to rotate the vacuum drum. A pill shelf is positioned adjacent to the front wall of the vacuum drum and a pill separator removes pills retained on the pill apertures while a pill sensor detects pills which are removed by the pill separator and exit the discharge aperture.
Other examples of singulating devices that rely upon a rotating drum having openings at which a vacuum is present are found in U.S. Pat. No. 3,770,164 entitled Singulator for Seeds or the Like (see particularly FIG. 7) and U.S. publication no. 2003/0116068 A1 entitled Vacuum Seed Meter and Dispensing Apparatus.